Estimation Of Genetic Parameters And Genetic Trend Analysis Of Yorkshire Pig By Using Different Models

This study was based on the Yorkshire pigs in National Core Breeding Farm in Fujian Province from 2010 to 2016 .Different genetic parameter models were designedto estimate heritability, geneticcorrelation coefficient and the breeding value by using Derivative Free Restricted Maximum Likelihood and Best Linear Unbiased Prediction,and analyze the phenotypic trends and genetic trends. The results are as follows:(1) Age at 100kg(AGE100)was gradually reduced from 2010 to 2016; Backfat thickness at 100kg(BF100)was in a stable wave; The result show : Values of Age at 100kg and Values of Backfat thickness at 100kgin sire population was all significantly lower than that in dam population. Total number born of piglets in the first and the eleven parity is the lowest, and total number born of piglets from the second parity to the fifth parity reached the peak and then decreased.(2) The individual direct additive genetic effects, the maternal direct additive genetic effects, individual and maternal direct additive genetic correlation coefficient of Age and Backfat thickness at 100kg were respectively 0.24696, 0.02074,-0.04522; 0.58055,0.07667, -0.14974. The individual direct additive genetic effects, the maternal direct additive genetic effects, individual and maternal direct additive genetic correlation coefficient of Total number born(TNB), Number born alive(NBA) and Litter weight born(LWB) were0.13543, 0.05101, -0.05886; 0.08763, 0.02931, -0.02526; 0.07423,0.01342, -0.00949. It can be seen that the maternal genetic effect has aneffect on the direct genetic effects of reproductive traits and production traits, and maternal genetic effect on reproductive traits are significant.(3)The genetic correlation coefficient of Age at 100kg( AGE 100) and Backfat thickness at 100kg(BF100), Total number born(TNB) and Number born alive(NBA),Total number born(TNB) and Litter weight born(LWB), Number born alive(NBA) and Litter weight born(LWB) were respectively-0.165,0.720,0.66, 0.540.(4)The phenotypic trend and genetic trend of Age at 100kg( AGE 100) of the boar from 2010 to 2016 were -2.20, -1.57, and the difference was significant (p <0.001);Besides phenotypic trend and genetic trend of Backfat thickness at 100kg were -0.169,-0.0480 for boar.The phenotypic trend and genetic trend of Age at 100kg( AGE 100) of the sow from 2010 to 2016 were -0.769, -1.59,and the difference was significant (p <0.001);Phenotypic trend and genetic trend of Back fat thickness at 100KG were -0.0680?-0.0501 for sow; finally phenotypic trend and genetic trend of Total number born(TNB)were 0.0860?0.00500 for sow,and the difference was significant (p <0.01).